Heart disease is the leading cause of death in the U.S. During acute myocardial infarction (one of the most common diagnoses of early heart disease) a part of the heart muscle tissue is damaged beyond repair, which can lead to congestive heart failure, an incurable condition. Therefore, there is a strong need to develop treatments for patients with damaged heart tissue. The proposed research aims to develop novel 3D cell-scaffolds that guide tissue development. Since heart muscle tissue consists of highly aligned myofibers, a scaffold that promotes tissue formation and tissue alignment is essential. To accomplish these design requirements, a highly porous scaffold will be designed where channels are introduced through photo-patterning. To promote and maintain cell differentiation, skeletal myoblasts or primary cardiac myocytes will be suspended in a pre-hydrogel solution and seeded onto the scaffold. Upon gelation, the cells will be embedded in a 3D tissue-like microenvironment while the macroenvironment promotes unidirectional growth of myofibers. The micro-(gel) and macro-(porous scaffold) environments can be fine tuned independently to match tissue growth.